The present disclosure relates to a mechanism for trimming sheet metal stampings. More particularly, a trimming die and interchangeable spring loaded scrap cutter is disclosed.
In the manufacture of automobile body panels such as fenders, hoods and deck lids, it is relatively common practice to form large stampings by one or more sheet metal drawing operations. To perform the drawing operation, a steel sheet is positioned between moveable drawing dies. The pre-formed sheet is typically oversized to allow material to flow into the cavities of the dies during the drawing operation. In some instances, the excess material at the perimeter of the sheet is clamped during the drawing process.
After the drawing operation has been completed, a trimming operation is performed to remove excess material from the perimeter of the formed component. The trimming operation is typically performed by a set of trim dies separate from the forming dies. During the trimming operation it is sometimes challenging to accurately remove a small amount of material about the perimeter of the formed part in an accurate and expeditious manner. In particular, when large contoured panels such as hoods are formed, a correspondingly large and unwieldy ring is separated from the panel during the trimming operation. It is desirable to remove the formed panel and the scrap trim ring from the die as quickly and as completely as possible.
Scrap cutters have been mounted within trim dies to cut the trim ring into two or more pieces to facilitate removal of the scrap from the trim die. Challenges have arisen when attempting to package portions of the trim die operable to perform the trimming operation and the tooling necessary to cut the scrap within a common envelope. In one known arrangement, the trim dies and scrap cutter components are positioned such that a majority, but not all, of the formed panel is separated from the trim ring during a first portion of the press stroke. As the trim and forming dies continue to move toward one another, the remaining portion of the trim ring is separated from the workpiece by the scrap cutters at the same time that the trim ring is cut into multiple pieces. Unfortunately, this die arrangement and procedure produces undesirable slivers of material that sometimes remain in the trim and/or forming die after the workpiece and the larger scrap pieces are removed. When the subsequent panel to be trimmed enters the die set, the sliver of material interferes with the trimming die, the scrap cutter and/or the workpiece to the extent that the die set or the part to be formed is damaged. Undesirable down time and repair costs result. Accordingly, there is a need in the art for an improved trimming die and spring loaded scrap cutter.